1. Field of the Invention
The present invention relates to the analysis of regional ventricular function and, more particularly, to the so called the centerline method of regional wall motion analysis which facilitates quantitative assessments of the regional ventricular wall motion.
2. Description of the Background Art
Conventionally, the assessments of the regional ventricular wall motion has depended on a subjective analysis using the contrast ventriculograms. Recently, the poor reproducibility of such qualitative evaluations has led to the development of various quantitative methods for measuring the regional ventricular wall motion.
Among such quantitative methods, the centerline method has attracted much attentions for its sensitivity and specificity in detecting abnormal regional functions as well as for its reliability, as can be seen from `Advantages and applications of the centerline method for characterizing regional ventricular function` by F. L. Sheehan, et al, Circulation 74, No. 2, pp. 293-305, August 1986, and the references therein.
A detail of the conventional centerline method can be found in this reference, and some of its salient points will be reviewed in relation to the present invention in DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS below. Here, one of the major problem encountered by the conventional centerline method will be summarized, without the technical detail.
In short, the essential feature of the centerline method is its use of a centerline with respect to which the lines are drawn between the end-diastolic and end-systolic contours, from which the wall motion is assessed by looking at the variations of the lengths of these lines. This centerline is actually determined from other preliminary lines also drawn between the end-diastolic and end-systolic contours. Thus, in the centerline method, drawing of the lines between the end-diastolic and end-systolic contours, required to be done twice, plays a critical role.
However, cares exercised in drawing these lines in the conventional centerline method has been proved to be inadequate for obtaining the sufficiently natural results, especially in the vicinity of the apex. This insufficient naturalness of the results in the vicinity of the apex has been one of the major limitation on the applicability of the centerline method.